Development of an enzymatic aptasensor for monitoring recombinant His-tagged proteins in microbial biotechnology

The utilization of polyhistidine tags (His-tag) for the purification and analysis of recombinant proteins is a widely adopted technique in biotechnology. Considering the high costs associated with antibody-based methods, the development of cost-effective techniques for protein identification following purification could significantly lower research expenses. This study developed a novel His-tag aptasensor, combining an anti-His tag aptamer with a G-quadruplex-based DNAzyme, which demonstrates limits of detection (LODs) of 0.29 μM and 0.73 μM for a His-tagged protein in calorimetric and point-of-care assays, respectively. These LODs are significantly lower than typical protein concentrations obtained through Ni-NTA affinity chromatography, indicating that the His-tag aptasensor provides an efficient solution for in vitro analysis and post-purification monitoring of His-tagged proteins.